1. Field of the Invention
This invention relates to mortarless interlocking building blocks for assembly in longitudinally staggered rows, and more particularly to a rectangularly shaped building block with a system of interlocking ribs and recesses.
2. Brief Description of the Prior Art
The laying of building blocks is a major labor cost in buildng construction, and there is a continuing need for building blocks which may be economically assembled to produce energy efficient, strong and durable structures. There are several patents disclosing building blocks which address this problem.
Rabassa, U.S. Pat. No. 4,314,431 discloses a generally rectangular mortarless interlocking building block having a single trapezoidal protrusion along the center of the top side, and a single trapezoidal slot along the center of the bottom side capable of receiving the protrusion and leaving a longitudinal space above the protrusion. A longitudinal opening extends through the block between the slot and protrusion that acts as a thermal and acoustic insulator and may be also be used to route conduit and wiring through it.
Caputo et al, U.S. Pat. No. 3,416,276 discloses a wall constructed of generally rectangular cored building blocks having a tongue on the top end and a groove on the bottom end. The blocks are laid with the larger dimensioned side surfaces vertical and the ends with the tongues and grooves horizontal. The blocks laid in this manner eliminates one course of blocks for every two courses as compared with conventional rectangular block wall construction.
Zagray, U.S. Pat. No. 3,534,518 discloses an interlocking rectangular building block construction having a pair of longitudinal ribs with flat top surfaces along the upper longitudinal face near the opposite sides of the block and a correspondingly shaped longitudinal recess is formed in the lower longitudinal face. A longitudinal groove having downwardly and inwardly converging side walls and a flat bottom wall is centrally located between the ribs, and a corresponding groove is located in the recess. A central vertical aperture extends through the block midway between the vertical end faces and communicates with the upper and lower grooves. Oppositely disposed, transverse, narrow flat extensions of the apparatus terminate near the opposite side of the block.
The prior art in general, and these patents in particular, do not disclose the system of interlocking rectangular building block of novel construction which comprises this invention.